Drillakilla

Drillkillas are small vessels, which look similar to Hulks. They are powered by treadwheels which have a special, experimental system of chain gearing attached to a drill. The gears are very erratic and constantly need to be adjusted in motion (this is done by thumping them with a hammer).[1a]

Because of the complex gearing system the crew of Drillkillas tend to need more rest than others and work in spurts, meaning that Drillkilla movement can be very erratic.[1b]

Drillkillas operate in squadrons of three and their uncertain movement often proves a problem when trying to maintain squadron formation.[1b]

Once a Drillkilla comes into contact with an enemy the drill starts to dig into its enemy.[1c]